/*
*    Qizx/open 3.0 beta
*
* This code is the open-source version of Qizx.
* Copyright (C) 2004-2009 Axyana Software -- All rights reserved.
*
* The contents of this file are subject to the Mozilla Public License 
*  Version 1.1 (the "License"); you may not use this file except in 
*  compliance with the License. You may obtain a copy of the License at
*  http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
*  WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
*  for the specific language governing rights and limitations under the
*  License.
*
* The Initial Developer of the Original Code is Xavier Franc - Axyana Software.
*
*/
using System;
using DataModelException = System.Qizx.Api.DataModelException;
using EvaluationException = System.Qizx.Api.EvaluationException;
using BasicNode = System.Qizx.Xdm.BasicNode;
using EvalContext = System.Qizx.XQuery.EvalContext;
using Focus = System.Qizx.XQuery.Focus;
using XQValue = System.Qizx.XQuery.XQValue;
using SingleBoolean = System.Qizx.XQuery.Dt.SingleBoolean;
namespace System.Qizx.XQuery.Op
{
	
	/// <summary> Operator 'isnot'.</summary>
	public class IsNotOp:NodeComparison
	{
		public IsNotOp(Expression expr1, Expression expr2):base(expr1, expr2)
		{
		}
		
		public override XQValue eval(Focus focus, EvalContext context)
		{
			XQValue n1 = expr1.eval(focus, context);
			XQValue n2 = expr2.eval(focus, context);
			try
			{
				return (!n1.Next() || !n2.Next())?System.Qizx.XQuery.XQValues.Empty:new SingleBoolean(n1.GetNode().DocumentOrderCompareTo(n2.GetNode()) != 0);
			}
			catch (DataModelException e)
			{
				throw BasicNode.WrapDMException(e);
			}
		}
		
		public override bool evalAsBoolean(Focus focus, EvalContext context)
		{
			XQValue n1 = expr1.eval(focus, context);
			XQValue n2 = expr2.eval(focus, context);
			try
			{
				return (!n1.Next() || !n2.Next())?false:n1.GetNode().DocumentOrderCompareTo(n2.GetNode()) != 0;
			}
			catch (DataModelException e)
			{
				throw BasicNode.WrapDMException(e);
			}
		}
	}
}